Geography Reference
In-Depth Information
nitric acids. Ironically, part of the acid-rain problem comes from earlier attempts to clear local polluted
air by raising smokestack heights. All that managed to do was dissipate the pollutants higher into the at-
mosphere, where they could blow into the neighbor's backyard; Canada's problems come from the United
States and London's dirty air blows into Norway.
When these industrial pollutants combine with water vapor, sunlight, and oxygen in the atmosphere,
they create a diluted soup of sulfuric and nitric acids. This appetizing mixture is then washed out of the
atmosphere by rain, snow crystals, or in the form of dry particles. Eventually, it reaches the water cycle,
increasing the acidity of freshwater lakes, streams, and soils. Nearly a quarter of Sweden's ninety thousand
lakes are acidified to some extent. Fish can no longer survive in four thousand of them. In Norway, many
lakes and streams are technically dead. And in the eastern United States, thousands of lakes are now too
acidic to support fish. Trout and salmon no longer reproduce in nine acidic rivers in Nova Scotia.
In parts of Pennsylvania, the result is a corrosive solvent a thousand times as acidic as natural rain. So
far, the worst hit by the acid rain nightmare are northeastern regions of Canada and the United States, Cen-
tral Europe, and Scandinavia. But Australia and Brazil are also noticing early signs of the deadly rain.
Objects ranging from the Great Pyramids and the Sphinx to the great architectural landmarks of Europe
are being eaten by acidic smogs. The masonry of Cologne (Köln) cathedral is being eaten away. Many of
Europe's stained-glass windows are fading. In West Germany, the Black Forest has lost one third of its
trees, and many scientists attribute this trend to a combination of acid rain and other forms of air pollu-
tion. It is difficult to assess the costs of acid-rain damage. But it has been estimated that damage to metals,
buildings, and paint in European countries costs around $20 billion a year, and that does not include costs
of dead forests, acidified lakes, and damaged crops. Damage to the West German timber industry alone is
estimated at $800 million, plus an additional $600 million in agricultural losses due to reduced productiv-
ity.
Acid rain—with other human assistance in the form of logging, clearing of forests for cattle pasture,
wood cutting for fuel by half the world's population—is killing off one of nature's best defenses of the
atmosphere, the world's forests.
As they used to teach us in grade school, “forests are our friends.” They play major roles in the planet-
ary recycling of carbon, nitrogen, and oxygen—in other words, “in with the bad air, out with the good air.”
Forests help to determine temperature and rainfall. They are often at the source of great river systems and
protect soil from eroding. They constitute the major gene reservoirs of our planet, and they are the main
sites of the emergence of new species.
Wood was once one of the earth's most plentiful resources. But it has been treated badly. In 1950, 30
percent of the land was covered by forest, half of which was tropical forest. By 1975, the area covered by
tropical forest had declined to 12 percent.
After a bitter fight with the Canadian government, the United States reluctantly acknowledged the prob-
lem and began taking action to reduce emissions. Large fossil-fuel power plants were supposed to cut
emissions of sulfur dioxide by about 40 percent by 1988. Under the Clean Air Act of 1990, the United
States created a new program called “cap and trade.” It allowed power-plant operators to buy, sell, and
trade credits to continue to pollute as long as they reduced overall emissions by half.
The program proved largely successful, as the
San Francisco Chronicle
reported in 2007. In 2000, the
Environmental Protection Agency began the second phase, where nearly all power-generating units were
forced to reduce their sulfur dioxide output or buy credits from plants that cut their emissions. Plants that
miss the targets face stiff fines—two thousand dollars per excess ton. At the time the legislation was being
debated, many environmental groups were suspicious of the idea of a pollution credits trading program.
Some dubbed it a “license to pollute.”
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